The present disclosure herein relates to magnetic shielding sheets, and more particularly, to magnetic shielding sheets including metal strips and a magnetic sheet.
In line with an increase in the number of devices using electromagnetic waves, a phenomenon frequently occurs in which people are exposed to the electromagnetic waves in everyday life. In particular, it is difficult to shield or absorb a magnetic field generated from an electromagnetic source with a low-frequency band. In general, an electric field is shielded with a conductor if one wants to shield the electric field. However, if one wants to shield a magnetic field, it is difficult to shield the magnetic field with a metal due to heat loss. Thus, it is in general to shield the magnetic field with a magnetic material with a high magnetic permeability such as ferrite.
Since the material with a high magnetic permeability, such as ferrite, has very low conductivity and high magnetic permeability, it has advantages in that there is almost no heat loss. However, such a magnetic material is relatively expensive and has characteristics in which the magnetic permeability varies according to a frequency.
When a magnetic field is applied to a surface of a metallic material having high conductivity such as aluminum, an eddy current is generated on the surface of the metal by a boundary condition. Heat may be generated on the surface of the metal due to the eddy current, and since another magnetic field is formed in a direction opposite to a direction in which the magnetic field is applied, the two magnetic fields cancel each other. However, in a case in which a magnetic field is shielded with a metal, heat loss may be high when a strong magnetic field is applied.
Thus, the provision of a shielding sheet capable of efficiently shielding a magnetic field (additionally, capable of shielding an electric field) has emerged as an important issue.